Unmanned aerial vehicles (UAVs) have a maximum travel range due to a finite supply of onboard energy. In addition, the total energy that a particular unmanned aerial vehicle (UAV) may have available to operate is generally less than the full onboard energy because the UAV must keep some energy in reserve for maneuvers associated with landing and/or as a margin of error in case power measurements are inaccurate. If the UAV improperly gauges available onboard energy, the UAV may prematurely lose power and crash.